I have two questions on an assignment that require me to write two ε-δ Proofs. I understand the logic behind the ε-δ definition of a limit but I've never been asked to write a proof before and there aren't any examples in our book. I understand the semantics but not the syntax of what I need to do. One of the questions is: Give an ε-δ proof that: lim (2x+5) = -1 x-->(-3) I know from the definition of a limit that if 0<|x+3|<δ, then |2x+6|<ε. After doing some basic algebra, I know that δ = ε/2. So how do I write a proof with this information? I know that I could probably just put what I know into words and get credit (in fact, my prof told me to do exactly that) but I want to know how to write a tight formal proof.